/*****************************************************************************
* lcp.c - Network Link Control Protocol program file.
*
* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
* portions Copyright (c) 1997 by Global Election Systems Inc.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice and the following disclaimer are included verbatim in any
* distributions. No written agreement, license, or royalty fee is required
* for any of the authorized uses.
*
* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
* REVISION HISTORY
*
* 03-01-01 Marc Boucher <marc@mbsi.ca>
*   Ported to lwIP.
* 97-12-01 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
*   Original.
*****************************************************************************/

/*
 * lcp.c - PPP Link Control Protocol.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */


#include "lwip/opt.h"

#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */

#include "ppp_impl.h"
#include "pppdebug.h"

#include "fsm.h"
#include "chap.h"
#include "magic.h"
#include "auth.h"
#include "lcp.h"

#include <string.h>

#if PPPOE_SUPPORT
	#include "netif/ppp_oe.h"
#else
	#define PPPOE_MAXMTU PPP_MAXMRU
#endif

#if 0 /* UNUSED */
/*
 * LCP-related command-line options.
 */
int lcp_echo_interval = 0;  /* Interval between LCP echo-requests */
int lcp_echo_fails = 0;     /* Tolerance to unanswered echo-requests */
bool  lax_recv = 0;         /* accept control chars in asyncmap */

static int setescape(char**);

static option_t lcp_option_list[] = {
	/* LCP options */
	/* list stripped for simplicity */
	{NULL}
};
#endif /* UNUSED */

/* options */
LinkPhase lcp_phase[NUM_PPP];          /* Phase of link session (RFC 1661) */
static u_int lcp_echo_interval      = LCP_ECHOINTERVAL; /* Interval between LCP echo-requests */
static u_int lcp_echo_fails         = LCP_MAXECHOFAILS; /* Tolerance to unanswered echo-requests */

/* global vars */
static fsm lcp_fsm[NUM_PPP];                            /* LCP fsm structure (global)*/
lcp_options lcp_wantoptions[NUM_PPP];  /* Options that we want to request */
lcp_options lcp_gotoptions[NUM_PPP];   /* Options that peer ack'd */
lcp_options lcp_allowoptions[NUM_PPP]; /* Options we allow peer to request */
lcp_options lcp_hisoptions[NUM_PPP];   /* Options that we ack'd */
ext_accm xmit_accm[NUM_PPP];           /* extended transmit ACCM */

static u32_t lcp_echos_pending      = 0;                /* Number of outstanding echo msgs */
static u32_t lcp_echo_number        = 0;                /* ID number of next echo frame */
static u32_t lcp_echo_timer_running = 0;                /* TRUE if a timer is running */

/* @todo: do we really need such a large buffer? The typical 1500 bytes seem too much. */
static u_char nak_buffer[PPP_MRU]; /* where we construct a nak packet */

/*
 * Callbacks for fsm code.  (CI = Configuration Information)
 */
static void lcp_resetci(fsm*);                    /* Reset our CI */
static int  lcp_cilen(fsm*);                      /* Return length of our CI */
static void lcp_addci(fsm*, u_char*, int*);       /* Add our CI to pkt */
static int  lcp_ackci(fsm*, u_char*, int);        /* Peer ack'd our CI */
static int  lcp_nakci(fsm*, u_char*, int);        /* Peer nak'd our CI */
static int  lcp_rejci(fsm*, u_char*, int);        /* Peer rej'd our CI */
static int  lcp_reqci(fsm*, u_char*, int*, int);  /* Rcv peer CI */
static void lcp_up(fsm*);                         /* We're UP */
static void lcp_down(fsm*);                       /* We're DOWN */
static void lcp_starting(fsm*);                   /* We need lower layer up */
static void lcp_finished(fsm*);                   /* We need lower layer down */
static int  lcp_extcode(fsm*, int, u_char, u_char*, int);
static void lcp_rprotrej(fsm*, u_char*, int);

/*
 * routines to send LCP echos to peer
 */

static void lcp_echo_lowerup(int);
static void lcp_echo_lowerdown(int);
static void LcpEchoTimeout(void*);
static void lcp_received_echo_reply(fsm*, int, u_char*, int);
static void LcpSendEchoRequest(fsm*);
static void LcpLinkFailure(fsm*);
static void LcpEchoCheck(fsm*);

static fsm_callbacks lcp_callbacks = { /* LCP callback routines */
	lcp_resetci,  /* Reset our Configuration Information */
	lcp_cilen,    /* Length of our Configuration Information */
	lcp_addci,    /* Add our Configuration Information */
	lcp_ackci,    /* ACK our Configuration Information */
	lcp_nakci,    /* NAK our Configuration Information */
	lcp_rejci,    /* Reject our Configuration Information */
	lcp_reqci,    /* Request peer's Configuration Information */
	lcp_up,       /* Called when fsm reaches LS_OPENED state */
	lcp_down,     /* Called when fsm leaves LS_OPENED state */
	lcp_starting, /* Called when we want the lower layer up */
	lcp_finished, /* Called when we want the lower layer down */
	NULL,         /* Called when Protocol-Reject received */
	NULL,         /* Retransmission is necessary */
	lcp_extcode,  /* Called to handle LCP-specific codes */
	"LCP"         /* String name of protocol */
};

/*
 * Protocol entry points.
 * Some of these are called directly.
 */

static void lcp_input(int, u_char*, int);
static void lcp_protrej(int);

struct protent lcp_protent = {
	PPP_LCP,
	lcp_init,
	lcp_input,
	lcp_protrej,
	lcp_lowerup,
	lcp_lowerdown,
	lcp_open,
	lcp_close,
#if PPP_ADDITIONAL_CALLBACKS
	lcp_printpkt,
	NULL,
#endif /* PPP_ADDITIONAL_CALLBACKS */
	1,
	"LCP",
#if PPP_ADDITIONAL_CALLBACKS
	NULL,
	NULL,
	NULL
#endif /* PPP_ADDITIONAL_CALLBACKS */
};

int lcp_loopbackfail = DEFLOOPBACKFAIL;

/*
 * Length of each type of configuration option (in octets)
 */
#define CILEN_VOID  2
#define CILEN_CHAR  3
#define CILEN_SHORT 4 /* CILEN_VOID + sizeof(short) */
#define CILEN_CHAP  5 /* CILEN_VOID + sizeof(short) + 1 */
#define CILEN_LONG  6 /* CILEN_VOID + sizeof(long) */
#define CILEN_LQR   8 /* CILEN_VOID + sizeof(short) + sizeof(long) */
#define CILEN_CBCP  3

#define CODENAME(x)  ((x) == CONFACK ? "ACK" : (x) == CONFNAK ? "NAK" : "REJ")

#if 0 /* UNUSED */
/*
 * setescape - add chars to the set we escape on transmission.
 */
static int
setescape(argv)
char** argv;
{
	int n, ret;
	char* p, *endp;

	p = *argv;
	ret = 1;

	while(*p) {
		n = strtol(p, &endp, 16);

		if(p == endp) {
			option_error("escape parameter contains invalid hex number '%s'", p);
			return 0;
		}

		p = endp;

		if(n < 0 || n == 0x5E || n > 0xFF) {
			option_error("can't escape character 0x%x", n);
			ret = 0;
		} else
			xmit_accm[0][n >> 5] |= 1 << (n & 0x1F);

		while(*p == ',' || *p == ' ')
			++p;
	}

	return ret;
}
#endif /* UNUSED */

/*
 * lcp_init - Initialize LCP.
 */
void
lcp_init(int unit)
{
	fsm*         f  = &lcp_fsm[unit];
	lcp_options* wo = &lcp_wantoptions[unit];
	lcp_options* ao = &lcp_allowoptions[unit];

	f->unit      = unit;
	f->protocol  = PPP_LCP;
	f->callbacks = &lcp_callbacks;

	fsm_init(f);

	wo->passive           = 0;
	wo->silent            = 0;
	wo->restart           = 0;               /* Set to 1 in kernels or multi-line implementations */
	wo->neg_mru           = 1;
	wo->mru               = PPP_DEFMRU;
	wo->neg_asyncmap      = 1;
	wo->asyncmap          = 0x00000000l;     /* Assume don't need to escape any ctl chars. */
	wo->neg_chap          = 0;               /* Set to 1 on server */
	wo->neg_upap          = 0;               /* Set to 1 on server */
	wo->chap_mdtype       = CHAP_DIGEST_MD5;
	wo->neg_magicnumber   = 1;
	wo->neg_pcompression  = 1;
	wo->neg_accompression = 1;
	wo->neg_lqr           = 0;               /* no LQR implementation yet */
	wo->neg_cbcp          = 0;

	ao->neg_mru           = 1;
	ao->mru               = PPP_MAXMRU;
	ao->neg_asyncmap      = 1;
	ao->asyncmap          = 0x00000000l;     /* Assume don't need to escape any ctl chars. */
	ao->neg_chap          = (CHAP_SUPPORT != 0);
	ao->chap_mdtype       = CHAP_DIGEST_MD5;
	ao->neg_upap          = (PAP_SUPPORT != 0);
	ao->neg_magicnumber   = 1;
	ao->neg_pcompression  = 1;
	ao->neg_accompression = 1;
	ao->neg_lqr           = 0;               /* no LQR implementation yet */
	ao->neg_cbcp          = (CBCP_SUPPORT != 0);

	/*
	 * Set transmit escape for the flag and escape characters plus anything
	 * set for the allowable options.
	 */
	memset(xmit_accm[unit], 0, sizeof(xmit_accm[0]));
	xmit_accm[unit][15] = 0x60;
	xmit_accm[unit][0]  = (u_char)((ao->asyncmap        & 0xFF));
	xmit_accm[unit][1]  = (u_char)((ao->asyncmap >> 8)  & 0xFF);
	xmit_accm[unit][2]  = (u_char)((ao->asyncmap >> 16) & 0xFF);
	xmit_accm[unit][3]  = (u_char)((ao->asyncmap >> 24) & 0xFF);
	LCPDEBUG(LOG_INFO, ("lcp_init: xmit_accm=%X %X %X %X\n",
	                    xmit_accm[unit][0],
	                    xmit_accm[unit][1],
	                    xmit_accm[unit][2],
	                    xmit_accm[unit][3]));

	lcp_phase[unit] = PHASE_INITIALIZE;
}


/*
 * lcp_open - LCP is allowed to come up.
 */
void
lcp_open(int unit)
{
	fsm*         f  = &lcp_fsm[unit];
	lcp_options* wo = &lcp_wantoptions[unit];

	f->flags = 0;

	if(wo->passive) {
		f->flags |= OPT_PASSIVE;
	}

	if(wo->silent) {
		f->flags |= OPT_SILENT;
	}

	fsm_open(f);

	lcp_phase[unit] = PHASE_ESTABLISH;
}


/*
 * lcp_close - Take LCP down.
 */
void
lcp_close(int unit, char* reason)
{
	fsm* f = &lcp_fsm[unit];

	if(lcp_phase[unit] != PHASE_DEAD) {
		lcp_phase[unit] = PHASE_TERMINATE;
	}

	if(f->state == LS_STOPPED && f->flags & (OPT_PASSIVE | OPT_SILENT)) {
		/*
		 * This action is not strictly according to the FSM in RFC1548,
		 * but it does mean that the program terminates if you do an
		 * lcp_close() in passive/silent mode when a connection hasn't
		 * been established.
		 */
		f->state = LS_CLOSED;
		lcp_finished(f);
	} else {
		fsm_close(f, reason);
	}
}


/*
 * lcp_lowerup - The lower layer is up.
 */
void
lcp_lowerup(int unit)
{
	lcp_options* wo = &lcp_wantoptions[unit];

	/*
	 * Don't use A/C or protocol compression on transmission,
	 * but accept A/C and protocol compressed packets
	 * if we are going to ask for A/C and protocol compression.
	 */
	ppp_set_xaccm(unit, &xmit_accm[unit]);
	ppp_send_config(unit, PPP_MRU, 0xffffffffl, 0, 0);
	ppp_recv_config(unit, PPP_MRU, 0x00000000l,
	                wo->neg_pcompression, wo->neg_accompression);
	peer_mru[unit] = PPP_MRU;
	lcp_allowoptions[unit].asyncmap = (u_long)xmit_accm[unit][0]
	                                  | ((u_long)xmit_accm[unit][1] << 8)
	                                  | ((u_long)xmit_accm[unit][2] << 16)
	                                  | ((u_long)xmit_accm[unit][3] << 24);
	LCPDEBUG(LOG_INFO, ("lcp_lowerup: asyncmap=%X %X %X %X\n",
	                    xmit_accm[unit][3],
	                    xmit_accm[unit][2],
	                    xmit_accm[unit][1],
	                    xmit_accm[unit][0]));

	fsm_lowerup(&lcp_fsm[unit]);
}


/*
 * lcp_lowerdown - The lower layer is down.
 */
void
lcp_lowerdown(int unit)
{
	fsm_lowerdown(&lcp_fsm[unit]);
}


/*
 * lcp_input - Input LCP packet.
 */
static void
lcp_input(int unit, u_char* p, int len)
{
	fsm* f = &lcp_fsm[unit];

	fsm_input(f, p, len);
}


/*
 * lcp_extcode - Handle a LCP-specific code.
 */
static int
lcp_extcode(fsm* f, int code, u_char id, u_char* inp, int len)
{
	u_char* magp;

	switch(code) {
		case PROTREJ:
			lcp_rprotrej(f, inp, len);
			break;

		case ECHOREQ:
			if(f->state != LS_OPENED) {
				break;
			}

			LCPDEBUG(LOG_INFO, ("lcp: Echo-Request, Rcvd id %d\n", id));
			magp = inp;
			PUTLONG(lcp_gotoptions[f->unit].magicnumber, magp);
			fsm_sdata(f, ECHOREP, id, inp, len);
			break;

		case ECHOREP:
			lcp_received_echo_reply(f, id, inp, len);
			break;

		case DISCREQ:
			break;

		default:
			return 0;
	}

	return 1;
}


/*
 * lcp_rprotrej - Receive an Protocol-Reject.
 *
 * Figure out which protocol is rejected and inform it.
 */
static void
lcp_rprotrej(fsm* f, u_char* inp, int len)
{
	int i;
	struct protent* protp;
	u_short prot;

	if(len < (int)sizeof(u_short)) {
		LCPDEBUG(LOG_INFO, ("lcp_rprotrej: Rcvd short Protocol-Reject packet!\n"));
		return;
	}

	GETSHORT(prot, inp);

	LCPDEBUG(LOG_INFO, ("lcp_rprotrej: Rcvd Protocol-Reject packet for %x!\n", prot));

	/*
	 * Protocol-Reject packets received in any state other than the LCP
	 * LS_OPENED state SHOULD be silently discarded.
	 */
	if(f->state != LS_OPENED) {
		LCPDEBUG(LOG_INFO, ("Protocol-Reject discarded: LCP in state %d\n", f->state));
		return;
	}

	/*
	 * Upcall the proper Protocol-Reject routine.
	 */
	for(i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
		if(protp->protocol == prot && protp->enabled_flag) {
			(*protp->protrej)(f->unit);
			return;
		}
	}

	LCPDEBUG(LOG_WARNING, ("Protocol-Reject for unsupported protocol 0x%x\n", prot));
}


/*
 * lcp_protrej - A Protocol-Reject was received.
 */
static void
lcp_protrej(int unit)
{
	LWIP_UNUSED_ARG(unit);
	/*
	 * Can't reject LCP!
	 */
	LCPDEBUG(LOG_WARNING, ("lcp_protrej: Received Protocol-Reject for LCP!\n"));
	fsm_protreject(&lcp_fsm[unit]);
}


/*
 * lcp_sprotrej - Send a Protocol-Reject for some protocol.
 */
void
lcp_sprotrej(int unit, u_char* p, int len)
{
	/*
	 * Send back the protocol and the information field of the
	 * rejected packet.  We only get here if LCP is in the LS_OPENED state.
	 */

	fsm_sdata(&lcp_fsm[unit], PROTREJ, ++lcp_fsm[unit].id, p, len);
}


/*
 * lcp_resetci - Reset our CI.
 */
static void
lcp_resetci(fsm* f)
{
	lcp_wantoptions[f->unit].magicnumber = magic();
	lcp_wantoptions[f->unit].numloops = 0;
	lcp_gotoptions[f->unit] = lcp_wantoptions[f->unit];
	peer_mru[f->unit] = PPP_MRU;
	auth_reset(f->unit);
}


/*
 * lcp_cilen - Return length of our CI.
 */
static int
lcp_cilen(fsm* f)
{
	lcp_options* go = &lcp_gotoptions[f->unit];

#define LENCIVOID(neg)  ((neg) ? CILEN_VOID : 0)
#define LENCICHAP(neg)  ((neg) ? CILEN_CHAP : 0)
#define LENCISHORT(neg) ((neg) ? CILEN_SHORT : 0)
#define LENCILONG(neg)  ((neg) ? CILEN_LONG : 0)
#define LENCILQR(neg)   ((neg) ? CILEN_LQR: 0)
#define LENCICBCP(neg)  ((neg) ? CILEN_CBCP: 0)
	/*
	 * NB: we only ask for one of CHAP and UPAP, even if we will
	 * accept either.
	 */
	return (LENCISHORT(go->neg_mru && go->mru != PPP_DEFMRU) +
	        LENCILONG(go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl) +
	        LENCICHAP(go->neg_chap) +
	        LENCISHORT(!go->neg_chap && go->neg_upap) +
	        LENCILQR(go->neg_lqr) +
	        LENCICBCP(go->neg_cbcp) +
	        LENCILONG(go->neg_magicnumber) +
	        LENCIVOID(go->neg_pcompression) +
	        LENCIVOID(go->neg_accompression));
}


/*
 * lcp_addci - Add our desired CIs to a packet.
 */
static void
lcp_addci(fsm* f, u_char* ucp, int* lenp)
{
	lcp_options* go = &lcp_gotoptions[f->unit];
	u_char* start_ucp = ucp;

#define ADDCIVOID(opt, neg) \
  if (neg) { \
    LCPDEBUG(LOG_INFO, ("lcp_addci: opt=%d\n", opt)); \
    PUTCHAR(opt, ucp); \
    PUTCHAR(CILEN_VOID, ucp); \
  }
#define ADDCISHORT(opt, neg, val) \
  if (neg) { \
    LCPDEBUG(LOG_INFO, ("lcp_addci: INT opt=%d %X\n", opt, val)); \
    PUTCHAR(opt, ucp); \
    PUTCHAR(CILEN_SHORT, ucp); \
    PUTSHORT(val, ucp); \
  }
#define ADDCICHAP(opt, neg, val, digest) \
  if (neg) { \
    LCPDEBUG(LOG_INFO, ("lcp_addci: CHAP opt=%d %X\n", opt, val)); \
    PUTCHAR(opt, ucp); \
    PUTCHAR(CILEN_CHAP, ucp); \
    PUTSHORT(val, ucp); \
    PUTCHAR(digest, ucp); \
  }
#define ADDCILONG(opt, neg, val) \
  if (neg) { \
    LCPDEBUG(LOG_INFO, ("lcp_addci: L opt=%d %lX\n", opt, val)); \
    PUTCHAR(opt, ucp); \
    PUTCHAR(CILEN_LONG, ucp); \
    PUTLONG(val, ucp); \
  }
#define ADDCILQR(opt, neg, val) \
  if (neg) { \
    LCPDEBUG(LOG_INFO, ("lcp_addci: LQR opt=%d %lX\n", opt, val)); \
    PUTCHAR(opt, ucp); \
    PUTCHAR(CILEN_LQR, ucp); \
    PUTSHORT(PPP_LQR, ucp); \
    PUTLONG(val, ucp); \
  }
#define ADDCICHAR(opt, neg, val) \
  if (neg) { \
    LCPDEBUG(LOG_INFO, ("lcp_addci: CHAR opt=%d %X '%z'\n", opt, val, val)); \
    PUTCHAR(opt, ucp); \
    PUTCHAR(CILEN_CHAR, ucp); \
    PUTCHAR(val, ucp); \
  }

	ADDCISHORT(CI_MRU, go->neg_mru && go->mru != PPP_DEFMRU, go->mru);
	ADDCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl, go->asyncmap);
	ADDCICHAP(CI_AUTHTYPE, go->neg_chap, PPP_CHAP, go->chap_mdtype);
	ADDCISHORT(CI_AUTHTYPE, !go->neg_chap && go->neg_upap, PPP_PAP);
	ADDCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
	ADDCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
	ADDCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
	ADDCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
	ADDCIVOID(CI_ACCOMPRESSION, go->neg_accompression);

	if(ucp - start_ucp != *lenp) {
		/* this should never happen, because peer_mtu should be 1500 */
		LCPDEBUG(LOG_ERR, ("Bug in lcp_addci: wrong length\n"));
	}
}


/*
 * lcp_ackci - Ack our CIs.
 * This should not modify any state if the Ack is bad.
 *
 * Returns:
 *  0 - Ack was bad.
 *  1 - Ack was good.
 */
static int
lcp_ackci(fsm* f, u_char* p, int len)
{
	lcp_options* go = &lcp_gotoptions[f->unit];
	u_char cilen, citype, cichar;
	u_short cishort;
	u32_t cilong;

	/*
	 * CIs must be in exactly the same order that we sent.
	 * Check packet length and CI length at each step.
	 * If we find any deviations, then this packet is bad.
	 */
#define ACKCIVOID(opt, neg) \
  if (neg) { \
    if ((len -= CILEN_VOID) < 0) \
      goto bad; \
    GETCHAR(citype, p); \
    GETCHAR(cilen, p); \
    if (cilen != CILEN_VOID || citype != opt) \
      goto bad; \
  }
#define ACKCISHORT(opt, neg, val) \
  if (neg) { \
    if ((len -= CILEN_SHORT) < 0) \
      goto bad; \
    GETCHAR(citype, p); \
    GETCHAR(cilen, p); \
    if (cilen != CILEN_SHORT || citype != opt) \
      goto bad; \
    GETSHORT(cishort, p); \
    if (cishort != val) \
      goto bad; \
  }
#define ACKCICHAR(opt, neg, val) \
  if (neg) { \
    if ((len -= CILEN_CHAR) < 0) \
      goto bad; \
    GETCHAR(citype, p); \
    GETCHAR(cilen, p); \
    if (cilen != CILEN_CHAR || citype != opt) \
      goto bad; \
    GETCHAR(cichar, p); \
    if (cichar != val) \
      goto bad; \
  }
#define ACKCICHAP(opt, neg, val, digest) \
  if (neg) { \
    if ((len -= CILEN_CHAP) < 0) \
      goto bad; \
    GETCHAR(citype, p); \
    GETCHAR(cilen, p); \
    if (cilen != CILEN_CHAP || citype != opt) \
      goto bad; \
    GETSHORT(cishort, p); \
    if (cishort != val) \
      goto bad; \
    GETCHAR(cichar, p); \
    if (cichar != digest) \
      goto bad; \
  }
#define ACKCILONG(opt, neg, val) \
  if (neg) { \
    if ((len -= CILEN_LONG) < 0) \
      goto bad; \
    GETCHAR(citype, p); \
    GETCHAR(cilen, p); \
    if (cilen != CILEN_LONG ||  citype != opt) \
      goto bad; \
    GETLONG(cilong, p); \
    if (cilong != val) \
      goto bad; \
  }
#define ACKCILQR(opt, neg, val) \
  if (neg) { \
    if ((len -= CILEN_LQR) < 0) \
      goto bad; \
    GETCHAR(citype, p); \
    GETCHAR(cilen, p); \
    if (cilen != CILEN_LQR || citype != opt) \
      goto bad; \
    GETSHORT(cishort, p); \
    if (cishort != PPP_LQR) \
      goto bad; \
    GETLONG(cilong, p); \
    if (cilong != val) \
      goto bad; \
  }

	ACKCISHORT(CI_MRU, go->neg_mru && go->mru != PPP_DEFMRU, go->mru);
	ACKCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl, go->asyncmap);
	ACKCICHAP(CI_AUTHTYPE, go->neg_chap, PPP_CHAP, go->chap_mdtype);
	ACKCISHORT(CI_AUTHTYPE, !go->neg_chap && go->neg_upap, PPP_PAP);
	ACKCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
	ACKCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
	ACKCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
	ACKCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
	ACKCIVOID(CI_ACCOMPRESSION, go->neg_accompression);

	/*
	 * If there are any remaining CIs, then this packet is bad.
	 */
	if(len != 0) {
		goto bad;
	}

	LCPDEBUG(LOG_INFO, ("lcp_acki: Ack\n"));
	return (1);
bad:
	LCPDEBUG(LOG_WARNING, ("lcp_acki: received bad Ack!\n"));
	return (0);
}


/*
 * lcp_nakci - Peer has sent a NAK for some of our CIs.
 * This should not modify any state if the Nak is bad
 * or if LCP is in the LS_OPENED state.
 *
 * Returns:
 *  0 - Nak was bad.
 *  1 - Nak was good.
 */
static int
lcp_nakci(fsm* f, u_char* p, int len)
{
	lcp_options* go = &lcp_gotoptions[f->unit];
	lcp_options* wo = &lcp_wantoptions[f->unit];
	u_char citype, cichar, *next;
	u_short cishort;
	u32_t cilong;
	lcp_options no;     /* options we've seen Naks for */

	lcp_options try;    /* options to request next time */

	int looped_back = 0;
	int cilen;

	BZERO(&no, sizeof(no));

	try = *go;

	/*
	 * Any Nak'd CIs must be in exactly the same order that we sent.
	 * Check packet length and CI length at each step.
	 * If we find any deviations, then this packet is bad.
	 */
#define NAKCIVOID(opt, neg, code) \
  if (go->neg && \
      len >= CILEN_VOID && \
      p[1] == CILEN_VOID && \
      p[0] == opt) { \
    len -= CILEN_VOID; \
    INCPTR(CILEN_VOID, p); \
    no.neg = 1; \
    code \
  }
#define NAKCICHAP(opt, neg, code) \
  if (go->neg && \
      len >= CILEN_CHAP && \
      p[1] == CILEN_CHAP && \
      p[0] == opt) { \
    len -= CILEN_CHAP; \
    INCPTR(2, p); \
    GETSHORT(cishort, p); \
    GETCHAR(cichar, p); \
    no.neg = 1; \
    code \
  }
#define NAKCICHAR(opt, neg, code) \
  if (go->neg && \
      len >= CILEN_CHAR && \
      p[1] == CILEN_CHAR && \
      p[0] == opt) { \
    len -= CILEN_CHAR; \
    INCPTR(2, p); \
    GETCHAR(cichar, p); \
    no.neg = 1; \
    code \
  }
#define NAKCISHORT(opt, neg, code) \
  if (go->neg && \
      len >= CILEN_SHORT && \
      p[1] == CILEN_SHORT && \
      p[0] == opt) { \
    len -= CILEN_SHORT; \
    INCPTR(2, p); \
    GETSHORT(cishort, p); \
    no.neg = 1; \
    code \
  }
#define NAKCILONG(opt, neg, code) \
  if (go->neg && \
      len >= CILEN_LONG && \
      p[1] == CILEN_LONG && \
      p[0] == opt) { \
    len -= CILEN_LONG; \
    INCPTR(2, p); \
    GETLONG(cilong, p); \
    no.neg = 1; \
    code \
  }
#define NAKCILQR(opt, neg, code) \
  if (go->neg && \
      len >= CILEN_LQR && \
      p[1] == CILEN_LQR && \
      p[0] == opt) { \
    len -= CILEN_LQR; \
    INCPTR(2, p); \
    GETSHORT(cishort, p); \
    GETLONG(cilong, p); \
    no.neg = 1; \
    code \
  }

	/*
	 * We don't care if they want to send us smaller packets than
	 * we want.  Therefore, accept any MRU less than what we asked for,
	 * but then ignore the new value when setting the MRU in the kernel.
	 * If they send us a bigger MRU than what we asked, accept it, up to
	 * the limit of the default MRU we'd get if we didn't negotiate.
	 */
	if(go->neg_mru && go->mru != PPP_DEFMRU) {
		NAKCISHORT(CI_MRU, neg_mru,

		if(cishort <= wo->mru || cishort < PPP_DEFMRU) {
		try.mru = cishort;
	}
	          );
	}

	/*
	 * Add any characters they want to our (receive-side) asyncmap.
	 */
	if(go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl) {
		NAKCILONG(CI_ASYNCMAP, neg_asyncmap,
		          try.asyncmap = go->asyncmap | cilong;
		         );
	}

	/*
	 * If they've nak'd our authentication-protocol, check whether
	 * they are proposing a different protocol, or a different
	 * hash algorithm for CHAP.
	 */
	if((go->neg_chap || go->neg_upap)
	        && len >= CILEN_SHORT
	        && p[0] == CI_AUTHTYPE && p[1] >= CILEN_SHORT && p[1] <= len) {
		cilen = p[1];
		len -= cilen;
		no.neg_chap = go->neg_chap;
		no.neg_upap = go->neg_upap;
		INCPTR(2, p);
		GETSHORT(cishort, p);

		if(cishort == PPP_PAP && cilen == CILEN_SHORT) {
			/*
			 * If we were asking for CHAP, they obviously don't want to do it.
			 * If we weren't asking for CHAP, then we were asking for PAP,
			 * in which case this Nak is bad.
			 */
			if(!go->neg_chap) {
				goto bad;
			}

			try.neg_chap = 0;

		} else if(cishort == PPP_CHAP && cilen == CILEN_CHAP) {
			GETCHAR(cichar, p);

			if(go->neg_chap) {
				/*
				 * We were asking for CHAP/MD5; they must want a different
				 * algorithm.  If they can't do MD5, we'll have to stop
				 * asking for CHAP.
				 */
				if(cichar != go->chap_mdtype) {
					try.neg_chap = 0;
				}
			} else {
				/*
				 * Stop asking for PAP if we were asking for it.
				 */
				try.neg_upap = 0;
			}

		} else {
			/*
			 * We don't recognize what they're suggesting.
			 * Stop asking for what we were asking for.
			 */
			if(go->neg_chap) {
				try.neg_chap = 0;
			} else {
				try.neg_upap = 0;
			}

			p += cilen - CILEN_SHORT;
		}
	}

	/*
	 * If they can't cope with our link quality protocol, we'll have
	 * to stop asking for LQR.  We haven't got any other protocol.
	 * If they Nak the reporting period, take their value XXX ?
	 */
	NAKCILQR(CI_QUALITY, neg_lqr,

	if(cishort != PPP_LQR) {
	try.neg_lqr = 0;
} else {
	try.lqr_period = cilong;
}
        );

	/*
	 * Only implementing CBCP...not the rest of the callback options
	 */
	NAKCICHAR(CI_CALLBACK, neg_cbcp,
	          try.neg_cbcp = 0;
	         );

	/*
	 * Check for a looped-back line.
	 */
	NAKCILONG(CI_MAGICNUMBER, neg_magicnumber,
	          try.magicnumber = magic();
	          looped_back = 1;
	         );

	/*
	 * Peer shouldn't send Nak for protocol compression or
	 * address/control compression requests; they should send
	 * a Reject instead.  If they send a Nak, treat it as a Reject.
	 */
	NAKCIVOID(CI_PCOMPRESSION, neg_pcompression,
	          try.neg_pcompression = 0;
	         );
	NAKCIVOID(CI_ACCOMPRESSION, neg_accompression,
	          try.neg_accompression = 0;
	         );

	/*
	 * There may be remaining CIs, if the peer is requesting negotiation
	 * on an option that we didn't include in our request packet.
	 * If we see an option that we requested, or one we've already seen
	 * in this packet, then this packet is bad.
	 * If we wanted to respond by starting to negotiate on the requested
	 * option(s), we could, but we don't, because except for the
	 * authentication type and quality protocol, if we are not negotiating
	 * an option, it is because we were told not to.
	 * For the authentication type, the Nak from the peer means
	 * `let me authenticate myself with you' which is a bit pointless.
	 * For the quality protocol, the Nak means `ask me to send you quality
	 * reports', but if we didn't ask for them, we don't want them.
	 * An option we don't recognize represents the peer asking to
	 * negotiate some option we don't support, so ignore it.
	 */
	while(len > CILEN_VOID) {
		GETCHAR(citype, p);
		GETCHAR(cilen, p);

		if(cilen < CILEN_VOID || (len -= cilen) < 0) {
			goto bad;
		}

		next = p + cilen - 2;

		switch(citype) {
			case CI_MRU:
				if((go->neg_mru && go->mru != PPP_DEFMRU)
				        || no.neg_mru || cilen != CILEN_SHORT) {
					goto bad;
				}

				GETSHORT(cishort, p);

				if(cishort < PPP_DEFMRU) {
					try.mru = cishort;
				}

				break;

			case CI_ASYNCMAP:
				if((go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl)
				        || no.neg_asyncmap || cilen != CILEN_LONG) {
					goto bad;
				}

				break;

			case CI_AUTHTYPE:
				if(go->neg_chap || no.neg_chap || go->neg_upap || no.neg_upap) {
					goto bad;
				}

				break;

			case CI_MAGICNUMBER:
				if(go->neg_magicnumber || no.neg_magicnumber ||
				        cilen != CILEN_LONG) {
					goto bad;
				}

				break;

			case CI_PCOMPRESSION:
				if(go->neg_pcompression || no.neg_pcompression
				        || cilen != CILEN_VOID) {
					goto bad;
				}

				break;

			case CI_ACCOMPRESSION:
				if(go->neg_accompression || no.neg_accompression
				        || cilen != CILEN_VOID) {
					goto bad;
				}

				break;

			case CI_QUALITY:
				if(go->neg_lqr || no.neg_lqr || cilen != CILEN_LQR) {
					goto bad;
				}

				break;
		}

		p = next;
	}

	/* If there is still anything left, this packet is bad. */
	if(len != 0) {
		goto bad;
	}

	/*
	* OK, the Nak is good.  Now we can update state.
	*/
	if(f->state != LS_OPENED) {
		if(looped_back) {
			if(++try.numloops >= lcp_loopbackfail) {
				LCPDEBUG(LOG_NOTICE, ("Serial line is looped back.\n"));
				lcp_close(f->unit, "Loopback detected");
			}
		} else {
			try.numloops = 0;
		}

		*go = try;
	}

	return 1;

bad:
	LCPDEBUG(LOG_WARNING, ("lcp_nakci: received bad Nak!\n"));
	return 0;
}


/*
 * lcp_rejci - Peer has Rejected some of our CIs.
 * This should not modify any state if the Reject is bad
 * or if LCP is in the LS_OPENED state.
 *
 * Returns:
 *  0 - Reject was bad.
 *  1 - Reject was good.
 */
static int
lcp_rejci(fsm* f, u_char* p, int len)
{
	lcp_options* go = &lcp_gotoptions[f->unit];
	u_char cichar;
	u_short cishort;
	u32_t cilong;

	lcp_options try; /* options to request next time */

	try = *go;

	/*
	 * Any Rejected CIs must be in exactly the same order that we sent.
	 * Check packet length and CI length at each step.
	 * If we find any deviations, then this packet is bad.
	 */
#define REJCIVOID(opt, neg) \
  if (go->neg && \
      len >= CILEN_VOID && \
      p[1] == CILEN_VOID && \
      p[0] == opt) { \
    len -= CILEN_VOID; \
    INCPTR(CILEN_VOID, p); \
    try.neg = 0; \
    LCPDEBUG(LOG_INFO, ("lcp_rejci: void opt %d rejected\n", opt)); \
  }
#define REJCISHORT(opt, neg, val) \
  if (go->neg && \
      len >= CILEN_SHORT && \
      p[1] == CILEN_SHORT && \
      p[0] == opt) { \
    len -= CILEN_SHORT; \
    INCPTR(2, p); \
    GETSHORT(cishort, p); \
    /* Check rejected value. */ \
    if (cishort != val) { \
      goto bad; \
    } \
    try.neg = 0; \
    LCPDEBUG(LOG_INFO, ("lcp_rejci: short opt %d rejected\n", opt)); \
  }
#define REJCICHAP(opt, neg, val, digest) \
  if (go->neg && \
      len >= CILEN_CHAP && \
      p[1] == CILEN_CHAP && \
      p[0] == opt) { \
    len -= CILEN_CHAP; \
    INCPTR(2, p); \
    GETSHORT(cishort, p); \
    GETCHAR(cichar, p); \
    /* Check rejected value. */ \
    if (cishort != val || cichar != digest) { \
      goto bad; \
    } \
    try.neg = 0; \
    try.neg_upap = 0; \
    LCPDEBUG(LOG_INFO, ("lcp_rejci: chap opt %d rejected\n", opt)); \
  }
#define REJCILONG(opt, neg, val) \
  if (go->neg && \
      len >= CILEN_LONG && \
      p[1] == CILEN_LONG && \
      p[0] == opt) { \
    len -= CILEN_LONG; \
    INCPTR(2, p); \
    GETLONG(cilong, p); \
    /* Check rejected value. */ \
    if (cilong != val) { \
      goto bad; \
    } \
    try.neg = 0; \
    LCPDEBUG(LOG_INFO, ("lcp_rejci: long opt %d rejected\n", opt)); \
  }
#define REJCILQR(opt, neg, val) \
  if (go->neg && \
      len >= CILEN_LQR && \
      p[1] == CILEN_LQR && \
      p[0] == opt) { \
    len -= CILEN_LQR; \
    INCPTR(2, p); \
    GETSHORT(cishort, p); \
    GETLONG(cilong, p); \
    /* Check rejected value. */ \
    if (cishort != PPP_LQR || cilong != val) { \
      goto bad; \
    } \
    try.neg = 0; \
    LCPDEBUG(LOG_INFO, ("lcp_rejci: LQR opt %d rejected\n", opt)); \
  }
#define REJCICBCP(opt, neg, val) \
  if (go->neg && \
      len >= CILEN_CBCP && \
      p[1] == CILEN_CBCP && \
      p[0] == opt) { \
    len -= CILEN_CBCP; \
    INCPTR(2, p); \
    GETCHAR(cichar, p); \
    /* Check rejected value. */ \
    if (cichar != val) { \
      goto bad; \
    } \
    try.neg = 0; \
    LCPDEBUG(LOG_INFO, ("lcp_rejci: Callback opt %d rejected\n", opt)); \
  }

	REJCISHORT(CI_MRU, neg_mru, go->mru);
	REJCILONG(CI_ASYNCMAP, neg_asyncmap, go->asyncmap);
	REJCICHAP(CI_AUTHTYPE, neg_chap, PPP_CHAP, go->chap_mdtype);

	if(!go->neg_chap) {
		REJCISHORT(CI_AUTHTYPE, neg_upap, PPP_PAP);
	}

	REJCILQR(CI_QUALITY, neg_lqr, go->lqr_period);
	REJCICBCP(CI_CALLBACK, neg_cbcp, CBCP_OPT);
	REJCILONG(CI_MAGICNUMBER, neg_magicnumber, go->magicnumber);
	REJCIVOID(CI_PCOMPRESSION, neg_pcompression);
	REJCIVOID(CI_ACCOMPRESSION, neg_accompression);

	/*
	 * If there are any remaining CIs, then this packet is bad.
	 */
	if(len != 0) {
		goto bad;
	}

	/*
	 * Now we can update state.
	 */
	if(f->state != LS_OPENED) {

		*go = try;
	}

	return 1;

bad:
	LCPDEBUG(LOG_WARNING, ("lcp_rejci: received bad Reject!\n"));
	return 0;
}


/*
 * lcp_reqci - Check the peer's requested CIs and send appropriate response.
 *
 * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
 * appropriately.  If reject_if_disagree is non-zero, doesn't return
 * CONFNAK; returns CONFREJ if it can't return CONFACK.
 */
static int
lcp_reqci(fsm* f,
          u_char* inp,    /* Requested CIs */
          int* lenp,      /* Length of requested CIs */
          int reject_if_disagree)
{
	lcp_options* go = &lcp_gotoptions[f->unit];
	lcp_options* ho = &lcp_hisoptions[f->unit];
	lcp_options* ao = &lcp_allowoptions[f->unit];
	u_char* cip, *next;         /* Pointer to current and next CIs */
	int cilen, citype;          /* Parsed len, type */
	u_char cichar;              /* Parsed char value */
	u_short cishort;            /* Parsed short value */
	u32_t cilong;               /* Parse long value */
	int rc = CONFACK;           /* Final packet return code */
	int orc;                    /* Individual option return code */
	u_char* p;                  /* Pointer to next char to parse */
	u_char* rejp;               /* Pointer to next char in reject frame */
	u_char* nakp;               /* Pointer to next char in Nak frame */
	int l = *lenp;              /* Length left */
#if TRACELCP > 0
	char traceBuf[80];
	size_t traceNdx = 0;
#endif

	/*
	 * Reset all his options.
	 */
	BZERO(ho, sizeof(*ho));

	/*
	 * Process all his options.
	 */
	next = inp;
	nakp = nak_buffer;
	rejp = inp;

	while(l) {
		orc = CONFACK;      /* Assume success */
		cip = p = next;     /* Remember begining of CI */

		if(l < 2 ||         /* Not enough data for CI header or */
		        p[1] < 2 ||     /*  CI length too small or */
		        p[1] > l) {     /*  CI length too big? */
			LCPDEBUG(LOG_WARNING, ("lcp_reqci: bad CI length!\n"));
			orc = CONFREJ;    /* Reject bad CI */
			cilen = l;        /* Reject till end of packet */
			l = 0;            /* Don't loop again */
			citype = 0;
			goto endswitch;
		}

		GETCHAR(citype, p); /* Parse CI type */
		GETCHAR(cilen, p);  /* Parse CI length */
		l -= cilen;         /* Adjust remaining length */
		next += cilen;      /* Step to next CI */

		switch(citype) {    /* Check CI type */
			case CI_MRU:
				if(!ao->neg_mru) {     /* Allow option? */
					LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject MRU - not allowed\n"));
					orc = CONFREJ;    /* Reject CI */
					break;
				} else if(cilen != CILEN_SHORT) {   /* Check CI length */
					LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject MRU - bad length\n"));
					orc = CONFREJ;    /* Reject CI */
					break;
				}

				GETSHORT(cishort, p);  /* Parse MRU */

				/*
				 * He must be able to receive at least our minimum.
				 * No need to check a maximum.  If he sends a large number,
				 * we'll just ignore it.
				 */
				if(cishort < PPP_MINMRU) {
					LCPDEBUG(LOG_INFO, ("lcp_reqci: Nak - MRU too small\n"));
					orc = CONFNAK;    /* Nak CI */
					PUTCHAR(CI_MRU, nakp);
					PUTCHAR(CILEN_SHORT, nakp);
					PUTSHORT(PPP_MINMRU, nakp);  /* Give him a hint */
					break;
				}

				ho->neg_mru = 1;    /* Remember he sent MRU */
				ho->mru = cishort;    /* And remember value */
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " MRU %d", cishort);
				traceNdx = strlen(traceBuf);
#endif
				break;

			case CI_ASYNCMAP:
				if(!ao->neg_asyncmap) {
					LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject ASYNCMAP not allowed\n"));
					orc = CONFREJ;
					break;
				} else if(cilen != CILEN_LONG) {
					LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject ASYNCMAP bad length\n"));
					orc = CONFREJ;
					break;
				}

				GETLONG(cilong, p);

				/*
				 * Asyncmap must have set at least the bits
				 * which are set in lcp_allowoptions[unit].asyncmap.
				 */
				if((ao->asyncmap & ~cilong) != 0) {
					LCPDEBUG(LOG_INFO, ("lcp_reqci: Nak ASYNCMAP %lX missing %lX\n",
					                    cilong, ao->asyncmap));
					orc = CONFNAK;
					PUTCHAR(CI_ASYNCMAP, nakp);
					PUTCHAR(CILEN_LONG, nakp);
					PUTLONG(ao->asyncmap | cilong, nakp);
					break;
				}

				ho->neg_asyncmap = 1;
				ho->asyncmap = cilong;
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " ASYNCMAP=%lX", cilong);
				traceNdx = strlen(traceBuf);
#endif
				break;

			case CI_AUTHTYPE:
				if(cilen < CILEN_SHORT) {
					LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject AUTHTYPE missing arg\n"));
					orc = CONFREJ;
					break;
				} else if(!(ao->neg_upap || ao->neg_chap)) {
					/*
					 * Reject the option if we're not willing to authenticate.
					 */
					LCPDEBUG(LOG_INFO, ("lcp_reqci: Reject AUTHTYPE not allowed\n"));
					orc = CONFREJ;
					break;
				}

				GETSHORT(cishort, p);

				/*
				 * Authtype must be UPAP or CHAP.
				 *
				 * Note: if both ao->neg_upap and ao->neg_chap are set,
				 * and the peer sends a Configure-Request with two
				 * authenticate-protocol requests, one for CHAP and one
				 * for UPAP, then we will reject the second request.
				 * Whether we end up doing CHAP or UPAP depends then on
				 * the ordering of the CIs in the peer's Configure-Request.
				 */

				if(cishort == PPP_PAP) {
					if(ho->neg_chap) {   /* we've already accepted CHAP */
						LCPDEBUG(LOG_WARNING, ("lcp_reqci: Reject AUTHTYPE PAP already accepted\n"));
						orc = CONFREJ;
						break;
					} else if(cilen != CILEN_SHORT) {
						LCPDEBUG(LOG_WARNING, ("lcp_reqci: Reject AUTHTYPE PAP bad len\n"));
						orc = CONFREJ;
						break;
					}

					if(!ao->neg_upap) {   /* we don't want to do PAP */
						LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE PAP not allowed\n"));
						orc = CONFNAK;  /* NAK it and suggest CHAP */
						PUTCHAR(CI_AUTHTYPE, nakp);
						PUTCHAR(CILEN_CHAP, nakp);
						PUTSHORT(PPP_CHAP, nakp);
						PUTCHAR(ao->chap_mdtype, nakp);
						break;
					}

					ho->neg_upap = 1;
#if TRACELCP > 0
					snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " PAP (%X)", cishort);
					traceNdx = strlen(traceBuf);
#endif
					break;
				}

				if(cishort == PPP_CHAP) {
					if(ho->neg_upap) {   /* we've already accepted PAP */
						LCPDEBUG(LOG_WARNING, ("lcp_reqci: Reject AUTHTYPE CHAP accepted PAP\n"));
						orc = CONFREJ;
						break;
					} else if(cilen != CILEN_CHAP) {
						LCPDEBUG(LOG_WARNING, ("lcp_reqci: Reject AUTHTYPE CHAP bad len\n"));
						orc = CONFREJ;
						break;
					}

					if(!ao->neg_chap) {   /* we don't want to do CHAP */
						LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE CHAP not allowed\n"));
						orc = CONFNAK;  /* NAK it and suggest PAP */
						PUTCHAR(CI_AUTHTYPE, nakp);
						PUTCHAR(CILEN_SHORT, nakp);
						PUTSHORT(PPP_PAP, nakp);
						break;
					}

					GETCHAR(cichar, p);  /* get digest type*/

					if(cichar != CHAP_DIGEST_MD5
#if MSCHAP_SUPPORT
					        && cichar != CHAP_MICROSOFT
#endif
					  ) {
						LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE CHAP digest=%d\n", (int)cichar));
						orc = CONFNAK;
						PUTCHAR(CI_AUTHTYPE, nakp);
						PUTCHAR(CILEN_CHAP, nakp);
						PUTSHORT(PPP_CHAP, nakp);
						PUTCHAR(ao->chap_mdtype, nakp);
						break;
					}

#if TRACELCP > 0
					snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CHAP %X,%d", cishort, (int)cichar);
					traceNdx = strlen(traceBuf);
#endif
					ho->chap_mdtype = cichar; /* save md type */
					ho->neg_chap = 1;
					break;
				}

				/*
				 * We don't recognize the protocol they're asking for.
				 * Nak it with something we're willing to do.
				 * (At this point we know ao->neg_upap || ao->neg_chap.)
				 */
				orc = CONFNAK;
				PUTCHAR(CI_AUTHTYPE, nakp);

				if(ao->neg_chap) {
					LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE %d req CHAP\n", cishort));
					PUTCHAR(CILEN_CHAP, nakp);
					PUTSHORT(PPP_CHAP, nakp);
					PUTCHAR(ao->chap_mdtype, nakp);
				} else {
					LCPDEBUG(LOG_WARNING, ("lcp_reqci: Nak AUTHTYPE %d req PAP\n", cishort));
					PUTCHAR(CILEN_SHORT, nakp);
					PUTSHORT(PPP_PAP, nakp);
				}

				break;

			case CI_QUALITY:
				GETSHORT(cishort, p);
				GETLONG(cilong, p);
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " QUALITY (%x %x)", cishort, (unsigned int) cilong);
				traceNdx = strlen(traceBuf);
#endif

				if(!ao->neg_lqr ||
				        cilen != CILEN_LQR) {
					orc = CONFREJ;
					break;
				}

				/*
				 * Check the protocol and the reporting period.
				 * XXX When should we Nak this, and what with?
				 */
				if(cishort != PPP_LQR) {
					orc = CONFNAK;
					PUTCHAR(CI_QUALITY, nakp);
					PUTCHAR(CILEN_LQR, nakp);
					PUTSHORT(PPP_LQR, nakp);
					PUTLONG(ao->lqr_period, nakp);
					break;
				}

				break;

			case CI_MAGICNUMBER:
				if(!(ao->neg_magicnumber || go->neg_magicnumber) ||
				        cilen != CILEN_LONG) {
					orc = CONFREJ;
					break;
				}

				GETLONG(cilong, p);
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " MAGICNUMBER (%lX)", cilong);
				traceNdx = strlen(traceBuf);
#endif

				/*
				 * He must have a different magic number.
				 */
				if(go->neg_magicnumber &&
				        cilong == go->magicnumber) {
					cilong = magic();  /* Don't put magic() inside macro! */
					orc = CONFNAK;
					PUTCHAR(CI_MAGICNUMBER, nakp);
					PUTCHAR(CILEN_LONG, nakp);
					PUTLONG(cilong, nakp);
					break;
				}

				ho->neg_magicnumber = 1;
				ho->magicnumber = cilong;
				break;


			case CI_PCOMPRESSION:
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " PCOMPRESSION");
				traceNdx = strlen(traceBuf);
#endif

				if(!ao->neg_pcompression ||
				        cilen != CILEN_VOID) {
					orc = CONFREJ;
					break;
				}

				ho->neg_pcompression = 1;
				break;

			case CI_ACCOMPRESSION:
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " ACCOMPRESSION");
				traceNdx = strlen(traceBuf);
#endif

				if(!ao->neg_accompression ||
				        cilen != CILEN_VOID) {
					orc = CONFREJ;
					break;
				}

				ho->neg_accompression = 1;
				break;

			case CI_MRRU:
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_MRRU");
				traceNdx = strlen(traceBuf);
#endif
				orc = CONFREJ;
				break;

			case CI_SSNHF:
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_SSNHF");
				traceNdx = strlen(traceBuf);
#endif
				orc = CONFREJ;
				break;

			case CI_EPDISC:
#if TRACELCP > 0
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_EPDISC");
				traceNdx = strlen(traceBuf);
#endif
				orc = CONFREJ;
				break;

			default:
#if TRACELCP
				snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " unknown %d", citype);
				traceNdx = strlen(traceBuf);
#endif
				orc = CONFREJ;
				break;
		}

endswitch:
#if TRACELCP

		if(traceNdx >= 80 - 32) {
			LCPDEBUG(LOG_INFO, ("lcp_reqci: rcvd%s\n", traceBuf));
			traceNdx = 0;
		}

#endif

		if(orc == CONFACK &&  /* Good CI */
		        rc != CONFACK) {  /*  but prior CI wasnt? */
			continue;           /* Don't send this one */
		}

		if(orc == CONFNAK) {      /* Nak this CI? */
			if(reject_if_disagree   /* Getting fed up with sending NAKs? */
			        && citype != CI_MAGICNUMBER) {
				orc = CONFREJ;        /* Get tough if so */
			} else {
				if(rc == CONFREJ) {   /* Rejecting prior CI? */
					continue;           /* Don't send this one */
				}

				rc = CONFNAK;
			}
		}

		if(orc == CONFREJ) {         /* Reject this CI */
			rc = CONFREJ;

			if(cip != rejp) {          /* Need to move rejected CI? */
				BCOPY(cip, rejp, cilen); /* Move it */
			}

			INCPTR(cilen, rejp);       /* Update output pointer */
		}
	}

	/*
	 * If we wanted to send additional NAKs (for unsent CIs), the
	 * code would go here.  The extra NAKs would go at *nakp.
	 * At present there are no cases where we want to ask the
	 * peer to negotiate an option.
	 */

	switch(rc) {
		case CONFACK:
			*lenp = (int)(next - inp);
			break;

		case CONFNAK:
			/*
			 * Copy the Nak'd options from the nak_buffer to the caller's buffer.
			 */
			*lenp = (int)(nakp - nak_buffer);
			BCOPY(nak_buffer, inp, *lenp);
			break;

		case CONFREJ:
			*lenp = (int)(rejp - inp);
			break;
	}

#if TRACELCP > 0

	if(traceNdx > 0) {
		LCPDEBUG(LOG_INFO, ("lcp_reqci: %s\n", traceBuf));
	}

#endif
	LCPDEBUG(LOG_INFO, ("lcp_reqci: returning CONF%s.\n", CODENAME(rc)));
	return (rc);      /* Return final code */
}


/*
 * lcp_up - LCP has come UP.
 */
static void
lcp_up(fsm* f)
{
	lcp_options* wo = &lcp_wantoptions[f->unit];
	lcp_options* ho = &lcp_hisoptions[f->unit];
	lcp_options* go = &lcp_gotoptions[f->unit];
	lcp_options* ao = &lcp_allowoptions[f->unit];

	if(!go->neg_magicnumber) {
		go->magicnumber = 0;
	}

	if(!ho->neg_magicnumber) {
		ho->magicnumber = 0;
	}

	/*
	 * Set our MTU to the smaller of the MTU we wanted and
	 * the MRU our peer wanted.  If we negotiated an MRU,
	 * set our MRU to the larger of value we wanted and
	 * the value we got in the negotiation.
	 */
	ppp_send_config(f->unit, LWIP_MIN(ao->mru, (ho->neg_mru ? ho->mru : PPP_MRU)),
	                (ho->neg_asyncmap ? ho->asyncmap : 0xffffffffl),
	                ho->neg_pcompression, ho->neg_accompression);
	/*
	 * If the asyncmap hasn't been negotiated, we really should
	 * set the receive asyncmap to ffffffff, but we set it to 0
	 * for backwards contemptibility.
	 */
	ppp_recv_config(f->unit, (go->neg_mru ? LWIP_MAX(wo->mru, go->mru) : PPP_MRU),
	                (go->neg_asyncmap ? go->asyncmap : 0x00000000),
	                go->neg_pcompression, go->neg_accompression);

	if(ho->neg_mru) {
		peer_mru[f->unit] = ho->mru;
	}

	lcp_echo_lowerup(f->unit); /* Enable echo messages */

	link_established(f->unit); /* The link is up; authenticate now */
}


/*
 * lcp_down - LCP has gone DOWN.
 *
 * Alert other protocols.
 */
static void
lcp_down(fsm* f)
{
	lcp_options* go = &lcp_gotoptions[f->unit];

	lcp_echo_lowerdown(f->unit);

	link_down(f->unit);

	ppp_send_config(f->unit, PPP_MRU, 0xffffffffl, 0, 0);
	ppp_recv_config(f->unit, PPP_MRU,
	                (go->neg_asyncmap ? go->asyncmap : 0x00000000),
	                go->neg_pcompression, go->neg_accompression);
	peer_mru[f->unit] = PPP_MRU;
}


/*
 * lcp_starting - LCP needs the lower layer up.
 */
static void
lcp_starting(fsm* f)
{
	link_required(f->unit); /* lwip: currently does nothing */
}


/*
 * lcp_finished - LCP has finished with the lower layer.
 */
static void
lcp_finished(fsm* f)
{
	link_terminated(f->unit); /* we are finished with the link */
}


#if PPP_ADDITIONAL_CALLBACKS
/*
 * print_string - print a readable representation of a string using
 * printer.
 */
static void
print_string(char* p, int len, void (*printer)(void*, char*, ...), void* arg)
{
	int c;

	printer(arg, "\"");

	for(; len > 0; --len) {
		c = *p++;

		if(' ' <= c && c <= '~') {
			if(c == '\\' || c == '"') {
				printer(arg, "\\");
			}

			printer(arg, "%c", c);
		} else {
			switch(c) {
				case '\n':
					printer(arg, "\\n");
					break;

				case '\r':
					printer(arg, "\\r");
					break;

				case '\t':
					printer(arg, "\\t");
					break;

				default:
					printer(arg, "\\%.3o", c);
			}
		}
	}

	printer(arg, "\"");
}


/*
 * lcp_printpkt - print the contents of an LCP packet.
 */
static char* lcp_codenames[] = {
	"ConfReq", "ConfAck", "ConfNak", "ConfRej",
	"TermReq", "TermAck", "CodeRej", "ProtRej",
	"EchoReq", "EchoRep", "DiscReq"
};

static int
lcp_printpkt(u_char* p, int plen, void (*printer)(void*, char*, ...), void* arg)
{
	int code, id, len, olen;
	u_char* pstart, *optend;
	u_short cishort;
	u32_t cilong;

	if(plen < HEADERLEN) {
		return 0;
	}

	pstart = p;
	GETCHAR(code, p);
	GETCHAR(id, p);
	GETSHORT(len, p);

	if(len < HEADERLEN || len > plen) {
		return 0;
	}

	if(code >= 1 && code <= sizeof(lcp_codenames) / sizeof(char*)) {
		printer(arg, " %s", lcp_codenames[code - 1]);
	} else {
		printer(arg, " code=0x%x", code);
	}

	printer(arg, " id=0x%x", id);
	len -= HEADERLEN;

	switch(code) {
		case CONFREQ:
		case CONFACK:
		case CONFNAK:
		case CONFREJ:

			/* print option list */
			while(len >= 2) {
				GETCHAR(code, p);
				GETCHAR(olen, p);
				p -= 2;

				if(olen < 2 || olen > len) {
					break;
				}

				printer(arg, " <");
				len -= olen;
				optend = p + olen;

				switch(code) {
					case CI_MRU:
						if(olen == CILEN_SHORT) {
							p += 2;
							GETSHORT(cishort, p);
							printer(arg, "mru %d", cishort);
						}

						break;

					case CI_ASYNCMAP:
						if(olen == CILEN_LONG) {
							p += 2;
							GETLONG(cilong, p);
							printer(arg, "asyncmap 0x%lx", cilong);
						}

						break;

					case CI_AUTHTYPE:
						if(olen >= CILEN_SHORT) {
							p += 2;
							printer(arg, "auth ");
							GETSHORT(cishort, p);

							switch(cishort) {
								case PPP_PAP:
									printer(arg, "pap");
									break;

								case PPP_CHAP:
									printer(arg, "chap");
									break;

								default:
									printer(arg, "0x%x", cishort);
							}
						}

						break;

					case CI_QUALITY:
						if(olen >= CILEN_SHORT) {
							p += 2;
							printer(arg, "quality ");
							GETSHORT(cishort, p);

							switch(cishort) {
								case PPP_LQR:
									printer(arg, "lqr");
									break;

								default:
									printer(arg, "0x%x", cishort);
							}
						}

						break;

					case CI_CALLBACK:
						if(olen >= CILEN_CHAR) {
							p += 2;
							printer(arg, "callback ");
							GETSHORT(cishort, p);

							switch(cishort) {
								case CBCP_OPT:
									printer(arg, "CBCP");
									break;

								default:
									printer(arg, "0x%x", cishort);
							}
						}

						break;

					case CI_MAGICNUMBER:
						if(olen == CILEN_LONG) {
							p += 2;
							GETLONG(cilong, p);
							printer(arg, "magic 0x%x", cilong);
						}

						break;

					case CI_PCOMPRESSION:
						if(olen == CILEN_VOID) {
							p += 2;
							printer(arg, "pcomp");
						}

						break;

					case CI_ACCOMPRESSION:
						if(olen == CILEN_VOID) {
							p += 2;
							printer(arg, "accomp");
						}

						break;
				}

				while(p < optend) {
					GETCHAR(code, p);
					printer(arg, " %.2x", code);
				}

				printer(arg, ">");
			}

			break;

		case TERMACK:
		case TERMREQ:
			if(len > 0 && *p >= ' ' && *p < 0x7f) {
				printer(arg, " ");
				print_string((char*)p, len, printer, arg);
				p += len;
				len = 0;
			}

			break;

		case ECHOREQ:
		case ECHOREP:
		case DISCREQ:
			if(len >= 4) {
				GETLONG(cilong, p);
				printer(arg, " magic=0x%x", cilong);
				p += 4;
				len -= 4;
			}

			break;
	}

	/* print the rest of the bytes in the packet */
	for(; len > 0; --len) {
		GETCHAR(code, p);
		printer(arg, " %.2x", code);
	}

	return (int)(p - pstart);
}
#endif /* PPP_ADDITIONAL_CALLBACKS */

/*
 * Time to shut down the link because there is nothing out there.
 */
static void
LcpLinkFailure(fsm* f)
{
	if(f->state == LS_OPENED) {
		LCPDEBUG(LOG_INFO, ("No response to %d echo-requests\n", lcp_echos_pending));
		LCPDEBUG(LOG_NOTICE, ("Serial link appears to be disconnected.\n"));
		lcp_close(f->unit, "Peer not responding");
	}
}

/*
 * Timer expired for the LCP echo requests from this process.
 */
static void
LcpEchoCheck(fsm* f)
{
	LcpSendEchoRequest(f);

	/*
	 * Start the timer for the next interval.
	 */
	LWIP_ASSERT("lcp_echo_timer_running == 0", lcp_echo_timer_running == 0);

	TIMEOUT(LcpEchoTimeout, f, lcp_echo_interval);
	lcp_echo_timer_running = 1;
}

/*
 * LcpEchoTimeout - Timer expired on the LCP echo
 */
static void
LcpEchoTimeout(void* arg)
{
	if(lcp_echo_timer_running != 0) {
		lcp_echo_timer_running = 0;
		LcpEchoCheck((fsm*) arg);
	}
}

/*
 * LcpEchoReply - LCP has received a reply to the echo
 */
static void
lcp_received_echo_reply(fsm* f, int id, u_char* inp, int len)
{
	u32_t magic;

	LWIP_UNUSED_ARG(id);

	/* Check the magic number - don't count replies from ourselves. */
	if(len < 4) {
		LCPDEBUG(LOG_WARNING, ("lcp: received short Echo-Reply, length %d\n", len));
		return;
	}

	GETLONG(magic, inp);

	if(lcp_gotoptions[f->unit].neg_magicnumber && magic == lcp_gotoptions[f->unit].magicnumber) {
		LCPDEBUG(LOG_WARNING, ("appear to have received our own echo-reply!\n"));
		return;
	}

	/* Reset the number of outstanding echo frames */
	lcp_echos_pending = 0;
}

/*
 * LcpSendEchoRequest - Send an echo request frame to the peer
 */
static void
LcpSendEchoRequest(fsm* f)
{
	u32_t lcp_magic;
	u_char pkt[4], *pktp;

	/*
	 * Detect the failure of the peer at this point.
	 */
	if(lcp_echo_fails != 0) {
		if(lcp_echos_pending >= lcp_echo_fails) {
			LcpLinkFailure(f);
			lcp_echos_pending = 0;
		}
	}

	/*
	 * Make and send the echo request frame.
	 */
	if(f->state == LS_OPENED) {
		lcp_magic = lcp_gotoptions[f->unit].magicnumber;
		pktp = pkt;
		PUTLONG(lcp_magic, pktp);
		fsm_sdata(f, ECHOREQ, (u_char)(lcp_echo_number++ & 0xFF), pkt, (int)(pktp - pkt));
		++lcp_echos_pending;
	}
}

/*
 * lcp_echo_lowerup - Start the timer for the LCP frame
 */

static void
lcp_echo_lowerup(int unit)
{
	fsm* f = &lcp_fsm[unit];

	/* Clear the parameters for generating echo frames */
	lcp_echos_pending      = 0;
	lcp_echo_number        = 0;
	lcp_echo_timer_running = 0;

	/* If a timeout interval is specified then start the timer */
	if(lcp_echo_interval != 0) {
		LcpEchoCheck(f);
	}
}

/*
 * lcp_echo_lowerdown - Stop the timer for the LCP frame
 */

static void
lcp_echo_lowerdown(int unit)
{
	fsm* f = &lcp_fsm[unit];

	if(lcp_echo_timer_running != 0) {
		UNTIMEOUT(LcpEchoTimeout, f);
		lcp_echo_timer_running = 0;
	}
}

#endif /* PPP_SUPPORT */
